Device for collecting samples of a liquid in a tank for in a chemical reaction vessel

ABSTRACT

An apparatus for collecting a sample of a liquid in a vessel. The apparatus includes a tube positioned vertically above the vessel, a cup for removing liquid from the vessel which has an inlet opening and an outlet opening, a device for displacing the cup vertically between a position in the vessel below the surface of the liquid, and another position in the tube above the vessel, a conduit branching off from the tube at a first point adjacent the raised position of the cup, a sample valve in the conduit for admitting liquid to a collector, and a mechanism for diverting liquid outflow from the cup into the conduit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for collecting samples of aliquid in a tank or in a chemical reaction vessel, and more particularlyto a device comprising a cup, which cup is provided with a cavity andwith openings for filling and for outflow, and which is fitted, so as tobe moveable by the action of a piston, in a guide tube which is fittedonto a tank or onto a chemical reaction vessel.

2. Description of Related Art

Devices for the collection of samples are utilized in the chemicalindustry for collecting samples of those liquids which are contained intanks or in chemical reaction vessels for the purpose of performinglaboratory analyses. These liquids are most often very toxic andvolatile; and consequently, the collecting of samples necessitates agreat many precautions, on the one hand, to spare the user from havingto come into contact with the toxic liquid, and, on the other hand, toprevent pollution resulting from the release of a toxic and volatileliquid into the surrounding air.

The heretofore known embodiments of devices for collecting samplespresent a great many disadvantages. In fact, the embodiments of priorart generally consist of devices provided with conduits which collectthe liquid by means of suction mechanisms or aspirating pumps, all ofwhich occasionally makes it impossible to collect the sample due to thefact that the liquid fails to rise in the collecting device when thereaction vessel is subjected to vacuum conditions or when the vaportension of the liquid is low. There are embodiments utilizing gaseswhich are intended to aspirate or to drive the sample of liquid tooutside of the reaction vessel; however, these embodiments present adisadvantage linked to the use of a gas under pressure, the chief hazardof which may be the bursting of a seam or joint, which may constitute agrave peril for the operator in case the gas were to escape outwards.What is more: all these devices of prior art exhibit a major drawback inthat they throw out into the atmosphere a significant quantity ofpolluted gases. An exemplified embodiment of a piston being displaceablein a tube is already known from U.S. Pat. No. 5,029,484; however, thisdevice presents the disadvantage of not being able to function except inan open appliance--which is to say that it can only function correctlyif the external pressure is equal to the pressure prevailing in the tankor in the chemical reaction vessel.

SUMMARY OF THE INVENTION

Thus, the object of the present invention consists in remedying theabovementioned disadvantages of the embodiments of prior art.

According to the principle of the invention, a cup provided with acavity and with openings for filling and for outflow is fitted, so as tobe moveable by the action of a piston, in a tube-which is fitted onto atank or onto a chemical reaction vessel. When in its lowered position,the cup is immersed in the liquid which is contained in the tank, andthe liquid makes its way into the cup through the openings for filling.Actuated by the piston, the cup is caused to rise in the tube until theoutflow conduit is located above the level of a ring which acts as acollector. Both the dimensions and the angle of the outflow conduit aredetermined in such a way as to enable the liquid to flow from the cup bygravity as a continuous thin stream of liquid following the course of aparabola until it arrives onto the collector, which then conveys it intoa sampling valve. The principle of the invention presents numerousadvantages, foremost of which is the fact that it permits the samplingof liquids, regardless of whatever conditions of pressure andtemperature may prevail in the interior of the reaction vessel. It makespossible the sampling of a liquid with a very low vapor tension or of aliquid subjected to vacuum conditions, and likewise even when the liquidis one that undergoes crystallization at room temperature. Anothersignificant advantage consists in the fact that the particularconstruction design of the outflow conduit serves to facilitate thecomplete emptying of the cup, and yet another advantage consists in thefact that the layout of the sampling device permits the device as awhole to be emptied and drained entirely of the liquid, which liquidthen returns directly into the tank or into the chemical reactionvessel. This advantage makes it possible to obtain a sample that isimmediately representative of the liquid as it exists at the time of thenext sampling. The principle of the invention presents the furtheradvantage of making possible the collection of samples in the course ofa distillation process or during a chemical reaction, without alterationof the pressure or vacuum prevailing in the interior of the reactionvessel. The slight loss of liquid which occurs during the passage fromthe lowered position of filling to the outflow position of the cup isnegligible, because the changing of position is accomplished in a verybrief period of time. The principle of the invention is alsocharacterized particularly by the fact that the thin stream of liquidflows towards the collecting conduit by following the trajectory of aparabola.

BRIEF DESCRIPTION OF THE DRAWINGS

The attached drawings illustrate diagrammatically and by way of examplethe principles of the invention.

FIG. 1 is an overall lateral cutaway view of the entire sampling devicein the position in which the cup undergoes filling.

FIG. 2 is an overall lateral cutaway view of the sampling device in theposition of outflow from the cup.

FIG. 3 is an overall lateral cutaway view of the device, showing anembodiment of the lower portion of a tube which is provided with aprotective sheath.

FIG. 4 is a detailed cutaway view of an embodiment of a cup.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a guide tube 1 is fitted onto achemical reaction vessel 2 which contains a liquid 3. A cup 4 isconnected to a rod 8, which is itself connected to a moveable device,which latter is constituted, by way of example, by a piston 9 and acylinder 10. Said cup 4 comprises a cavity 7, openings for filling 6 and6' and an outflow conduit 5. Said tube 1 is provided with an intakeopening 18 which constitutes an inlet conduit for the liquid and whichis connected by an intake valve 16 to a sampling valve 13. Said tube 1is also provided with an opening 19 which constitutes a conduit foremptying which is connected to a return valve 17, which latter is itselfconnected to the sampling-valve device 13. At the level of intakeopening 18, the tube 1 is provided with a collector 12 which isconstituted by a ring. A flow-inspection port 15 is emplaced between theintake valve 16 and the sampling valve 13. The liquid is collected inthe receptacle 14 by pulling on the obturating needle 22. The liquid 3contained in the tank 2 is kept in motion by a stirring device 20.

In its filling position, the cup is placed in the lowered position shownin FIG. 1, in which position the openings for filling 6 and 6' arelocated below the surface of the liquid 3, in such a way that the liquidfills the cavity 7 of the cup. As shown in FIG. 2, the intake valve 16is actuated in the opened position and the piston 9 is actuated in sucha way as to raise the cup into the raised position--that is to say, upto the position at which the outflow conduit 5 is located above thecollector 12. In this position, the liquid flows from the cup 4 throughthe outflow conduit 5 and forms a thin stream which follows thetrajectory of a parabola and which flows into the collector 12. Theliquid then flows through valve 16 towards the sampling valve 13. Thecompletion of the flow can be monitored in the flow-inspection port 15.Valve 16 is then closed; and, with the obturating needle 22 beingpulled, the necessary liquid can flow into the receptacle 14. As soon asthe quantity of liquid for sampling is deemed sufficient, the obturatingneedle 22 is returned to its closed position and valve 17 is opened insuch a way as to empty the sampling device of the superfluous liquid,which liquid can now flow through opening 19 and through the tube 1 andreturn to the chemical reaction vessel. During passage from the loweredposition of the cup to its raised position, a meager quantity of liquidmay flow through the outflow conduit 5 and return into the chemicalreaction vessel, all of which does not present any disadvantage sincethe speed at which the cup is displaced can be regulated in such a waythat the greater portion of the liquid filling the cavity still remainsin the cavity when the cup reaches its raised position.

FIG. 3 shows an embodiment which comprises a sheath 21 which is intendedto protect the cup from those turbulences of the liquid that may becaused by the stirring device 20.

FIG. 4 is a detailed view of the cup 4 which is provided with the cavity7, the openings for filling 6 and 6' and the outflow conduit 5. Theupper part of the cup is connected by a shaft 23 to a lower member 24 ofthe displacing mechanism.

FIGS. 1 and 2 show, by way of example, a displacing mechanism in theform of a piston which can be actuated by pneumatic means. The principleof the displacing mechanism is independent from the principle of theinvention itself, inasmuch as the rod 8 which is connected to the cupmay likewise be activated by a mechanical displacing device--with atoothed rack, for example--or by a magnetically operated device.

The sampling device as a whole can be constructed with various materialsthat are currently utilized in the chemical industry, for example, withstainless steel, the inert metals, enameled steel, teflon, glass, orwith linings of fluorocarbon resin.

What is claimed is:
 1. Apparatus for collecting a sample of a liquidcontained in a vessel, comprising:a tube positioned vertically above thevessel; a cup for removing liquid from the vessel and comprising aninlet opening and an outlet opening; means for displacing the cupvertically between a first position in the vessel below the surface ofthe liquid, and a second position in the tube above the vessel; aconduit branching off from and in flow communication with said tube at afirst point adjacent said second position; a sample valve in saidconduit for selectively admitting liquid flowing through said conduit toa collecting means; and a means for diverting liquid outflow from saidcup in said second position into said conduit.
 2. Apparatus according toclaim 1, additionally comprising an intake valve disposed in the conduitbetween the tube and the sample valve.
 3. Apparatus according to claim1, wherein the outlet opening is arranged at an angle in a lower portionof the cup to enable liquid flow out of the cup in a continuous thinstream.
 4. Apparatus according to claim 1, wherein the diverting meanshas a conical shape and comprises a trough for recovery of liquid. 5.Apparatus according to claim 1, wherein said conduit is in flowcommunication with said tube at a second point below said first point toform a continuous path for flow of liquid and return of liquid to thevessel.
 6. Apparatus according to claim 5, additionally comprising areturn valve disposed between said sample valve and said second point.7. Apparatus according to claim 1, wherein said means for displacingcomprises a piston and cylinder, and a rod passing through the tube andconnecting the piston to the cup.
 8. Apparatus according to claim 1,wherein the tube is extended in a lower portion by a protective sheath.9. Apparatus according to claim 1, wherein the vessel is a reactionvessel.
 10. Apparatus according to claim 1, wherein the vessel is atank.
 11. Method for collecting a sample of liquid from a vessel,comprising the steps of:a) extending a tube vertically above the vessel;b) disposing a cup having an inlet opening and outlet opening in thevessel below the surface of the liquid, and permitting liquid to flowinto the cup; c) disposing a conduit in flow communication with the tubeat a first point and a second point below the first point; d) disposingin the conduit, sequentially between the first point and the secondpoint, an internal intake valve, a sample valve for removing liquid fromthe conduit through an outlet, and an internal return valve; e)attaching a collection bottle to the outlet of the sample valve; f)raising the cup containing the liquid vertically to the first point inthe tube, and permitting liquid to drain from the cup into the conduit,with the return valve and the sample valve closed, and the intake valveopen; g) closing the intake valve and opening the sample valve,permitting a predetermined amount of liquid to flow into the collectionbottle; and h) subsequently closing the sample valve and opening thereturn valve to permit any liquid remaining to return to the vessel.